A blank window might display when you start Microsoft Lync 2010.
For more information about the similar issue with Office Communicator R2, click the following article number to view the article in the Microsoft Knowledge Base:
983215 A blank window opens unexpectedly when you start Office Communicator 2007 R2
Article ID: 2623821 - Last Review: Nov 19, 2011 - Revision: 1
Microsoft Lync 2010